(a) Field of the Invention
The present invention relates to the technology of air distillation.
(b) Description of Prior Art
Some industrial applications require important quantities of impure oxygen under various pressures: gasifying of carbon, gasifying of petroleum residues, direct reduction-melting of iron minerals, injection of carbon in blast furnaces, metallurgy of non-ferrous metals, etc.
On the other hand, some industrial applications require the simultaneous supplying, in large quantities, of practically pure oxygen and of impure oxygen under different pressures. This is for example the case of steel mills having oxygen converters and in which the blast furnace is supplied with oxygen or oxygen enriched air.
The invention aims at fulfilling such means in an economical manner, i.e. permitting, with relatively low investment and energy consumption, to produce impure oxygen at a purity and a pressure which are selected at will and, if necessary, the production of practically pure oxygen.